The present invention relates to a device for selectively securing a component card within a computer system chassis. More particularly, it relates to a tool-less latch for selectively locking a PCI card bulkhead to a chassis card bay, preferably adapted for low profile chassis applications.
Most modern day computer systems, in particular, computer systems designed for server applications, include a peripheral component interconnect (PCI) system that interconnects one or more microprocessors with selected PCI cards. The PCI cards are each uniquely designed to support a variety of applications and afford a user the ability to tailor the computer system for a desired end-use.
PCI-based computer systems are structurally configured to promote manual insertion/removal of the PCI card. To this end, the computer system generally includes a chassis maintaining various other components, such as microprocessor(s), power supply unit(s), hard disk drive(s), cooling fan(s), etc. In addition, the chassis forms an I/O card bay defining slots sized to receive PCI cards. The card bay accurately positions and maintains individual PCI cards relative to a connector board (or xe2x80x9cbackplanexe2x80x9d) for designated interface with the microprocessor(s) via appropriate PCI bus architecture.
A distinct advantage of PCI-based computer systems is the ability to easily remove one or more of the PCI cards for subsequent servicing, exchange, upgrading, etc. As originally conceived, removal of a PCI card from the card bay entailed shutting off power to all of the card bay slots (and thus, all of the inserted PCI cards). More recently, however, PCI-based computer systems are designed to allow removal of one or more PCI cards without an entire system shutdown. This feature is commonly referred to as xe2x80x9chot plugxe2x80x9d or xe2x80x9chot swapxe2x80x9d. For high-end applications, especially server applications, this hot plug attribute is essential.
Various mechanisms have been devised for securely mounting individual cards within the respective slots. As a point of reference, the PCI cards are commonly secured to bulkhead mounting bracket that is otherwise secured to the chassis card bay. With this in mind, early techniques entailed affixing the bulkhead to the chassis with a screw or pin. While viable, this methodology is not conducive to quick-release of the PCI card, and presents a distinct risk that the screw (or other hardware component) might unexpectedly fall into the chassis, leading to component damage. Alternatively, plastic clips have been developed, that, in theory, secure the PCI card to the chassis bay. These plastic clips are formed as part of the PCI card bulkhead, and thus eliminate the concerns associated with loose hardware (e.g., screws). Unfortunately, however, the plastic clip approach may not satisfactorily secure the card to the chassis bay on a consistent basis, and is susceptible to connection failures due to vibrational forces normally encountered during computer operation.
More recent computer server designs are designed to include a separate retention/actuator device that is otherwise mounted to the chassis bay. In general terms, these devices include individual latches that not only xe2x80x9clockxe2x80x9d the bulkhead to the chassis, but also initiate a slot power down operation normally required for a hot plug procedure. One example of an available PCI card retention/actuator device is described in U.S. Pat. No. 6,182,173.
In addition to implementation of a hot swap capability in conjunction with an acceptable card bulkhead mounting device, another design goal for future computer/server systems is reducing an overall size of the chassis itself. As a point of reference, the smallest industry-accepted server configuration incorporates a chassis having a xe2x80x9cstandardxe2x80x9d 4 U height. These highly compact servers are commonly employed in xe2x80x9crackedxe2x80x9d applications, whereby a number of server units are vertically aligned in an appropriately designed rack. A series of these loaded racks are then stored side-by-side in a centralized location. Of course, any reduction in the chassis height would allow additional server units to be stored on a single rack, thereby maximizing use of available space. In this regard, PCI cards have a height of approximately 3 U, so that it may be possible to produce a server unit having a chassis height of less than 4 U. Unfortunately, however, the retention devices described above are incompatible with a 3 U design. That is to say, most available PCI card retention devices have a relatively substantial height, such that when mounted to the chassis bay, the overall height of the chassis unit must exceed 3 U. In fact, unless the original technique of utilizing loose hardware (e.g., a screw) is employed to mount the PCI card bulkhead, the smallest chassis unit height that can be achieved is 3.5 U. This additional 0.5 U requirement effectively results in a 4 U design. Conversely, if screws or other loose hardware are used, an unacceptable risk of component damage arises for the reasons described above.
Manufacturers continually to strive to develop PCI-based computer systems, especially servers, with increased functionality and reduced size. In this regard, hot plug capabilities are universally desired. Unfortunately, existing techniques for securing PCI cards to the chassis bay present unacceptable risks or are not conducive to a 3 U chassis design. Therefore, a need exists for a latch device otherwise permanently mounted to the chassis that consistently locks a PCI card component in place, and preferably satisfies the spacing constraints associated with a 3 U chassis design.
One aspect of the present invention relates to a latch for selectively locking a PCI bulkhead to a computer chassis bay. The latch includes a shoulder, a handle, an engagement body, and a biasing member. The shoulder defines a longitudinal axis. The handle extends outwardly from the shoulder and defines a front, a back, and a bottom. The engagement body extends from the bottom of the handle opposite the shoulder. Finally, the biasing member extends outwardly from the shoulder adjacent the back of the handle. In this regard, the biasing member includes an intermediate section and a trailing section. The intermediate section extends from the shoulder and is configured to be compressible onto itself. The trailing section, on the other hand, is configured to selectively engage a wall of the chassis bay. The engagement body is configured to selectively engage a PCI bulkhead, thereby locking it relative to the chassis bay. With the above in mind, the latch is configured to be rotatable about the longitudinal axis between a locked position and an unlocked position. In the locked position, the engagement body locks the PCI bulkhead to the chassis bay. Further, the intermediate section of the biasing member biases the trailing section to lodge against the chassis such that the biasing member resists movement from the locked position. Conversely, in the unlocked position, the handle, and thus the engagement body, is rotated away from the PCI bulkhead so that the PCI card can be removed. In one preferred embodiment, the latch further includes a stop member extending outwardly from the shoulder and circumferentially spaced from the handle and the biasing member. In this regard, the stop member is configured to selectively engage a wall of the chassis bay in the locked position, thereby impeding overt rotation of the latch. In another preferred embodiment, the biasing member is a U-shaped body that tapers in cross-sectional profile.
Another aspect of the present invention relates to an enclosure device for a PCI computer system. The enclosure device includes a chassis, a card bay, and a latch. The card bay is formed by the chassis and defines a plurality of card slots, as well as an outer frame portion. The outer frame portion includes a base wall configured to receive a PCI bulkhead and a sidewall extending in a perpendicular fashion from the base wall. The latch is secured to the base wall adjacent one of the slots. In this regard, the latch includes a shoulder, a handle, an engagement body, and a biasing member. The shoulder defines a longitudinal axis. The handle extends outwardly from the shoulder and defines a front, a back, and a bottom. The engagement body extends from the bottom of the handle and is positioned opposite the shoulder. Finally, the biasing member extends outwardly from the shoulder adjacent the back of the handle, and includes a compressible intermediate section and a trailing section. In this regard, the intermediate section is compressible onto itself, whereas the trailing section is configured to selectively engage the sidewall of the chassis card bay. With the above configuration, the latch is rotatable between an unlocked position and a locked position. In the locked position, the handle positions the engagement body so as to lock a PCI bulkhead to the base wall. Further, in the locked position, the trailing section of the biasing member is lodged against the sidewall, with the intermediate section resisting movement of the trailing section from this lodged locked position. In one preferred embodiment, the chassis has a height of 3 U, and the latch is sized to not exceed 3 U spacing requirements. In another preferred embodiment, at least one of the card slots is adapted to be hot pluggable, and at least another one of the other slots is not. In this regard, the latch is color coded so as to signify whether the card slot with which the latch is associated is hot pluggable.